\documentclass{article}
\usepackage{multirow}

\begin{document}
\begin{figure*}
	\centering
	\begin{tabular}{|c|c|c c c c|c|}
		\hline
		\multicolumn{2}{|c|}{\multirow{2}{*}{$V_{\rm rot}/{\sigma}$}} & \multicolumn{4}{c|}{W1}                                                                \\
		\cline{3-6}
		\multicolumn{2}{|c|}{}                                        & 3                      & 6                   & 9                  & 12                 \\
		\hline
		\multirow{6}{*}{W2} & \multirow{3}{*}{3}                      & $0.090475\pm 0.011115$ & \multirow{3}{*}{21} & \multirow{3}{*}{6} & \multirow{3}{*}{3} \\
		                    &                                         & $0.14861\pm 0.03562$   &                     &                    &                    \\
		                    &                                         & $0.1861 \pm 0.01728$   &                     &                    &                    \\
		                    & 6                                       & 8                      & 14                  & 5                  & 2                  \\
		                    & 9                                       & 8                      & 14                  & 5                  & 2                  \\
		                    & 12                                      & 8                      & 14                  & 5                  & 2                  \\
		\hline
	\end{tabular}
	\caption{Multirow in multirow}
	\label{ta.Multirow}
\end{figure*}
\end{document}
